L'objectif est de tester la possibilite d'evaluer des resistances thermiques de contact par radiometrie photothermique, puis d'entreprendre son application au controle du sertissage dans des echangeurs. L'utilisation d'une excitation laser condiut a proposer deux modelisations bidimensionnelles axisymetriques applicables, en regime sinusoidal, a un materiau tri-couche. Le calcul du signal photothermique est effectue en prenant en compte l'ensemble des caracteristiques de la chaine de detection. Des echantillons calibres ont ete realises afin de confronter theorie et experience

Photothermal radiometry is a promising method for the non destructive testing and the characterization of thin materials and has already been suggested to study various kinds of layered materials. A bonding defect at the interface of two materials leads to a thermal contact resistance which is usually low and hardly detectable with the existing NDT techniques. We wish to present here the results of three studies of modulated photothermal radiometry for which such defects can be observed. At first, we have studied several metallic-electrochemically induced deposits. A statistical treatment allows to distinguish various samples, when prepared in different conditions. Then, a similar coating (black polyurethane paint) has been deposited on two plates (steel and glass), for which the bonding strength is known as different. Evidence is given of the existence of an interface thermal resistance for the coating deposited on glass. At last, we have studied the mechanical contact quality between two coaxial metallic pipes. A mathematical model has been developed, including a focalized laser excitation. We were thus able to measure very low contact resistances (about 10-5 S.I.).

Based on a previous experimental and theoretical study /1, 2/, we describe here a new method for the characterization of the thermophysical and structural parameters of the upper layer and/or the interface of semitransparent bilayered materials (thickness 1, thermal contact resistance R, thermal diffusivity α, absorption coefficient β).

Blood is essentially composed of a suspension of corpuscules (red and white blood cells, platelets) in a viscous liquid, the plasma. In the case of many human diseases, the suspension stability of blood is altered and the speed of sedimentation is accelerated, which can be measured with a standing test evaluating the evolution occurring after one or two hours.